Intrinsic Microporosity in Polyimides
AbstractPolymers with molecular structures that cannot pack efficiently in the solid state and therefore trap a large amount of free volume may be regarded as having “intrinsic microporosity” (effective pore dimensions <2 nm). Polymers of intrinsic microporosity (PIMs) typically have rigid backbones (e.g., ladder-like sequences) and incorporate sites of contortion (e.g., spiro-centers) that force the backbone to twist and turn. Here we describe a novel polyimide that incorporates features of a PIM. We also demonstrate that other polyimides that exhibit very high permeability to gases may be regarded as “intrinsically microporous”.